Identifying Patients With the COPD-Asthma Overlap Phenotype: Therapeutic Implications

Background: Asthma and COPD are considered different diseases but many patients share characteristics of both entities. This has been termed "COPD-asthma overlap syndrome". Study objective: To examine: (a) the frequency of the overlap phenotype among patients referred for pulmonary function testing and, (b) the impact of this phenotype on the therapeutic management and the quality of life of these patients as compared with patients with COPD only and asthma only. Methods: Type of study: Observational, cross-sectional. Study subjects: Patients referred for pulmonary function test diagnosed with airway obstruction (FEV1/FVC \ 10 pack/years and post-bronchodilator (BD) FEV1/FVC ratio of \< 0.70; b) Asthma only: (1) presence of wheezing in the last year plus a minimum post-BD increase in FEV1 or FVC of 12% and 200 ml; (2) prior physician diagnosis (before age 40); and c) both COPD-Asthma (the overlap group) - the combination of the two. Outcome measures: The clinical outcome is the prevalence rate of the phenotypes. Patient-reported outcomes will include the utilization of medication, the number of exacerbations, and quality of life.